Sieve flour and baking powder into a large bowl. Cube margarine and add. Rub in until mixture resembles breadcrumbs. Add the cheddar.

Break the egg into a measuring jug, add the milk to bring the measurement to 1/4 pt/150 mls and beat together. Add to the flour and mix to a smooth dough. Roll out on a floured work surface to about a 9"/23cm circle. Place on a lightly greased baking tray, or a pizza tray.

Slice tomatoes and mozzarella. Slice the courgette thinly with a peeler. Layer over pizza base.